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WCAG 2.0 for Usability Specialists

Bristol Usability Group
8 April 2010
Michael Cooper,

Michael Cooper

What is WCAG 2.0?

W3C Specifications

WCAG 2.0 materials

WCAG 2.0 Documents

WCAG 2.0 materials

WCAG Principles

Content must be…

Consider perspectives

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Do accessibility and usability overlap?

Or are they less related?

Accessibility becomes usability

"Usability" criteria in WCAG

The following slides are excerpted from WCAG 2.0. They present, in no particular order, some guidance that is important for people with disabilities and is also good for mainstream usability.

Note wording has been simplified in a manner that changes some details meaning; reference the original for full information.


Accommodate varied colour perception requirements and preferences.

Some people have visual perception issues that can be mitigated by using custom colours. Others have strong than average preferences for what facilitates their reading.


Allow users to customize presentation, without destroying the usability of the content.

Allowing users to customize presentation maximises utility to them. Site design should accommodate this, not force users to accommodate the design.


Ensure users who do not use a pointing device have full functionality.

Many users with disabilities do not use a pointing device. Others access content in situations in which it is not convenient to use a mouse or is faster to use the keyboard to navigate.


Accommodate slower than expected interaction whenever possible.

Some disabilities cause users to work more slowly, and users of assistive technologies may have to work more slowly as well. Situations such as distractions and interruptions can also cause users to slow down.


Avoid features that distract users from the main content.

Some users are more inconvienced by distractions than others, and can find it difficult to find their place again. Included here is a requirement that users not be "distracted" by seizures related to photosensitive epilepsy.

Orientation in Site

Provide information to orient users within the site. It can be difficult to find the desired content otherwise.

A site structure that is obvious to the developer is not always obvious to the user. A variety of features help users get oriented and work with different styles.

Orientation in Page

Provide features to orient users within the page. Not all users "grok" the overall page design.

Users of assistive technology may only perceive the page in small chunks at a time, or in a linear fashion, and it is easy to get lost even within a given page, or hard to find the content of interest. The same applies to users on small devices such as mobile phones or who "skim" content.


Support understanding of complex content.

Assistive technology can need support to render unusual words in a meaningful way. Some disabilities directly relate to ability to understand certain types of content. In general, people have a wide variety of reasons given content may be difficult to understand, such as accessing in a non-native language, or even just woke up!


Do not perform unexpected actions that cause users to get lost.

With some assistive technologies, it can be difficult to find your place again if something moves focus unexpectedly. In general interruptions are distracting and disorienting.


Help users avoid and correct input errors.

Often, input errors can be automatically detected. It is important to provide meaningful support when this happens, rather than just tell users something was wrong.


Properly identify controls and provide additional help where appropriate.

Identifying controls helps users use them properly.

WCAG Conformance

Thank you


Michael Cooper:

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